Self-consistent bulge/disk/halo galaxy dynamical modeling using integral field kinematics

We introduce a method for modeling disk galaxies designed to take full advantage of data from integral field spectroscopy (IFS). The method fits equilibrium models to simultaneously reproduce the surface brightness, rotation, and velocity dispersion profiles of a galaxy. The models are fully self-co...

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Bibliographic Details
Published in:The Astrophysical Journal
Main Authors: Taranu, D. S., Obreschkow, D., Dubinski, J. J., Fogarty, L. M. R., Sande, J. van de, Catinella, B., Cortese, L., Moffett, A., Robotham, A. S. G., Allen, J. T., Bland-Hawthorn, J., Bryant, J. J., Colless, M., Croom, S. M., D'Eugenio, F., Davies, R. L., Drinkwater, M. J., Driver, S. P., Goodwin, M., Konstantopoulos, I. S., Lawrence, J. S., López-Sánchez, Á. R., Lorente, N. P. F., Medling, A. M., Mould, J. R., Owers, M. S., Power, C., Richards, S. N., Tonini, C.
Other Authors: University of St Andrews. School of Physics and Astronomy
Format: Article in Journal/Newspaper
Language:English
Published: 2018
Subjects:
QB
QC
Online Access:http://hdl.handle.net/10023/12536
https://doi.org/10.3847/1538-4357/aa9221
http://arxiv.org/abs/1710.03241v1
Description
Summary:We introduce a method for modeling disk galaxies designed to take full advantage of data from integral field spectroscopy (IFS). The method fits equilibrium models to simultaneously reproduce the surface brightness, rotation, and velocity dispersion profiles of a galaxy. The models are fully self-consistent 6D distribution functions for a galaxy with a Sérsic profile stellar bulge, exponential disk, and parametric dark-matter halo, generated by an updated version of GalactICS. By creating realistic flux-weighted maps of the kinematic moments (flux, mean velocity, and dispersion), we simultaneously fit photometric and spectroscopic data using both maximum-likelihood and Bayesian (MCMC) techniques. We apply the method to a GAMA spiral galaxy (G79635) with kinematics from the SAMI Galaxy Survey and deep g- and r-band photometry from the VST-KiDS survey, comparing parameter constraints with those from traditional 2D bulge–disk decomposition. Our method returns broadly consistent results for shared parameters while constraining the mass-to-light ratios of stellar components and reproducing the H i-inferred circular velocity well beyond the limits of the SAMI data. Although the method is tailored for fitting integral field kinematic data, it can use other dynamical constraints like central fiber dispersions and H i circular velocities, and is well-suited for modeling galaxies with a combination of deep imaging and H i and/or optical spectra (resolved or otherwise). Our implementation (MagRite) is computationally efficient and can generate well-resolved models and kinematic maps in under a minute on modern processors. Publisher PDF Peer reviewed